Seal

ABSTRACT

The invention provides a seal ( 4, 5, 6, 7, 8 ) for sealing between two members ( 1, 3 ) which are mutually movable so. as to slide relative to each other. One of the members comprises a body ( 3 ) with a channel ( 2 ) formed therein. The channel ( 2 ) has a longitudinal axis and the other member ( 1 ) is receivable in the channel ( 2 ) so that the two members ( 1, 3 ) slide relative to each other in a direction parallel to the longitudinal axis. The first element ( 1 ) has at least one deformable plastics rib ( 4, 5, 6, 7, 8 ) formed on a surface thereof. The rib ( 4, 5, 6, 7, 8 ) faces the second element ( 3 ) and in use deforms on abutment with the wall of the channel ( 2 ) of the second member ( 3 ) to provide a seal between the two elements ( 1, 3 ) when they are stationary or moving relative to one another.

The present invention relates to a seal and in particular to a sealuseful in systems for the sterile transfer of fluids.

Validation and accountability are vital in most scientific industriesand especially so in the pharmaceutical and biotechnological industries.A major challenge to these industries is the need to demonstrateaccurately and reproducibly that sterility is achieved and maintainedthroughout production lines within a plant. This must be done in amanner which meets the stringent requirements of regulatory bodies suchas the United States FDA. Acceptable standards can be difficult to bemet when a substance is transferred from one sterile location to anothersterile location by non direct means. Reliable and durable seal meansmust be employed during such transfer.

The present invention provides a seal for sealing between two memberswhich are mutually movable so as to slide relative to each other, afirst one of the elements having formed on a surface thereof facing asecond of the elements at least one deformable plastics rib forcontacting the second member and sealing between the two elements whenthey are stationary or moving relative to one another.

In a most preferred embodiment, one of the members comprises a body witha channel formed therein, the channel having a longitudinal axis and theother member being receivable in the channel so that the two membersslide relative to each other in direction parallel to the longitudinalaxis, a first one of the elements having formed on a surface thereoffacing a second of the elements the at least one deformable plastics ribfor contacting the second member and sealing between the two elementswhen they are stationary or moving relative to one another.

Ideally, the first one of the two elements is constructed of plasticsmaterial and the rib may be formed integrally therewith.

The rib is sufficiently deformable and flexible so that it in effectdrags or wipes along the surface of the second element with which it isin contact as the two elements slide with respect to one another. Aplurality of sealing ribs may be provided, axially spaced apart from oneanother along the path of relative movement between the parts.

The rib itself may have different shapes and configurations, any ofwhich will be suitable provided that they are such as to provide aneffective seal between the parts. For example, the rib may be formedwith its free, sealing edge shaped as a U, V, W or any other suitablecross-sectional shape.

Of particular benefit is the use of such a sealing arrangement in avalve where a piston slides within a housing so as to open or close anopen end of the valve. In such a case, it is advantageous to form therib about the radially outwardly facing surface of the piston with therib extending radially outwardly therefrom to impinge upon the interiorsurface of the housing.

The seal of the present invention may have use as an alternative oraddition to known sealing means, such as an O-ring seal.

The invention will now be described with reference to the accompanyingdrawings which show, by way of example only, several embodiments of theseal according to the invention.

In the drawings:

FIG. 1 is a side elevation of a first embodiment a seal formed in acylindrical body;

FIG. 2 is an enlarged portion of FIG. 1 showing the seal;

FIG. 3 is a side elevation of a second embodiment a seal formed in acylindrical body;

FIG. 4 is an enlarged portion of FIG. 3 showing the seal;

FIG. 5 is a side elevation of a third embodiment a seal formed in acylindrical body;

FIG. 6 is an enlarged portion of FIG. 5 showing the seal;

FIG. 7 is a side elevation of a fourth embodiment a seal formed in acylindrical body;

FIG. 8 is an enlarged portion of FIG. 7 showing the seal;

FIG. 9 is a side elevation of a fifth embodiment a seal formed in acylindrical body;

FIG. 10 is an enlarged portion of FIG. 9 showing the seal;

FIG. 11 is a perspective view of a sliding piece having one seal of thefirst embodiment;

FIG. 12 is an elevation of a portion of a piston having three seals ofthe fourth embodiment;

FIG. 13 is an enlarged sectional view of a portion of FIG. 12 showingthe seals; and

FIG. 14 is a sectional elevation of a fourth embodiment of the seal usedin combination with an O-ring.

Referring to FIGS. 1 to 10 there is shown a cylinder 1 slidablyreceivable in a circular channel 2 of a body 3. A seal member accordingto the invention is provided in a form of deformable ribs 4, 5, 6, 7, 8of FIGS. 2, 4, 6, 8, and 10 respectively formed around the externalsurface of the cylinder 1. The rib 4 has a U-shape in cross section, theribs 5, 7 and 8 are V-shaped in cross-section and the rib 6 is W-shapedin cross-section. The diameter of the cylinder 1 is smaller than thediameter of the channel 2 whereas the most peripheral region 9 of thesurface of the rib 4, 5, 6, 7, 8 projects beyond the external surface 1a of the cylinder 1 so that the diameter of the most peripheral region 9is greater than the diameter of the channel 2. The cylinder 1 is made ofa plastics material and the rib 4, 5, 6, 7, 8 is formed integrally withthe cylinder. Other means of forming the rib on the cylinder are alsopossible.

In use, when the cylinder 1 is loaded into the channel 2, the mostperipheral region 9 of the surface of the rib 4, 5, 6, 7, 8 abuts thewall of the channel 2 and deforms in order to permit the cylinder 1 toenter the channel 2. The abutment is sufficiently close and tight that aseal is formed between the wall 10 and the rib 4, 5, 6, 7, 8. This sealremains intact during subsequent movements of the cylinder 1 along thechannel as the deformable rib 4, 5, 6, 7, 8 drags or “wipes” along thewall of the channel 2.

FIG. 11 shows a cylinder 1 in perspective having one rib 5.

FIGS. 12 and 13 show an end portion of a piston 12 for use in a valvefor sterile transfer of fluids. Such a piston is movable within ahousing of the valve in order to open or close an open end of thehousing. The piston 12 has three ribs 7 axially spaced apart from eachother along the path of the piston in the housing.

FIG. 14 shows a rib 7 formed around the external surface of a piston 14disposed in a channel 18 of a housing 15. The rib 7 is used incombination with an O-ring 16 received in a groove 17 of the piston 14to provide a seal between the exterior of the piston 14 and the wall ofthe channel 18.

The ribs 4, 5, 6, 7, 8 have been described as formed around a cylinder 1but of course such ribs 4, 5, 6, 7, 8 may be provided around the walldefining the channel 2 of the body 3 in order to form a seal between theexternal surface 1 a of a cylinder 1 received in the channel 2.

The seal member of the invention is not limited to use only in acylinder or in a circular channel and indeed can be provided around abody or around a wall of a channel of any cross-sectional shape, such asfor example square or any other shape suitable to provide a seal.Neither is the seal of the invention limited to sealing between elementswhich slide relative to one another about a common concentric axis.Rather, the seal of the invention can be used to seal between any twosurfaces which slide relative to each other. The rib will be providedsubstantially perpendicular to the axis substantially parallel to whichthe surfaces slide.

It will of course be understood that the invention is not limited to thespecific details as herein described, which are given by way of exampleonly, and that various alterations and modifications may be made withoutdeparting from the scope of the invention as defined in the appendedclaims.

1. A seal for sealing between two members which are mutually movable soas to slide relative to each other, a first one of the members havingformed on a surface thereof facing a second of the members at least onedeformable plastics rib for contacting the second member and sealingbetween the two members when they are stationary or moving relative toone another, and in which at least two ribs are formed on the surface ofthe first member so that the distance between the ribs alone the path oftravel of the two members relative one another is greater than apredetermined distance of travel of the two members relative to eachother along the path so as to allow one of the ribs to always remainwithin a predetermined area of the surface of the second member.
 2. Aseal as claimed in claim 1, in which the first one of the two members isconstructed of plastics material and the rib is formed integrallytherewith.
 3. A seal as claimed in claim 1, in which the rib issufficiently deformable and flexible so that it drags or wipes along thesurface of the second member with which it is in contact as the twoelements slide with respect to one another.
 4. (canceled)
 5. A seal asclaimed in claim 1, in which a plurality of the ribs is provided, theribs being axially spaced apart from one another along the path ofrelative movement between the parts.
 6. A seal as claimed in claim 1, inwhich one of the members comprises a body with a channel formed therein,the channel having a longitudinal axis and the other member beingreceivable in the channel so that the two members slide relative to eachother in a direction parallel to the longitudinal axis, a first one ofthe members having formed on a surface thereof facing a second of themembers the at least one deformable plastics rib.
 7. A seal as claimedin claim 6, in which an adaptor is provided between the wall of thechannel and the receivable member, the adaptor comprising an endlessskirt provided around a surface of one of the channel or the receivablemember facing the other member, the skirt being connected to the memberand being movable with the member so that mutually facing surfaces ofthe skirt and of the member to which the skirt is attached are spaced todefine a gap therebetween, the at least one deformable plastics ribbeing formed around one of the mutually facing surfaces of the skirt andsaid other member, the skirt being sufficiently deformable and flexiblein order to enable adjustment of the skirt to accommodate dimensionalirregularities between the skirt and said other member when the twomembers are engaged so as to allow the at least one rib to seal betweenthe mutually facing surfaces of the skirt and said other member when thetwo members are stationary or moving relative each other.
 8. A seal asclaimed in claim 7, in which the skirt comprises a free end portion anda base portion about which the skirt is connected to the member.
 9. Aseal as claimed in claim 7, in which the skirt is formed around thereceivable member and the rib is formed around the external surface ofthe skirt so that in use the skirt deforms in the channel to adjust todimensional irregularities between the external surface of the skirt andthe wall of the channel to enable the rib to seal therebetween.
 10. Aseal as claimed in claim 7, in which the skirt is sufficiently resilientto regain its original state upon withdrawal of deformation.
 11. A sealas claimed in claim 7, in which the skirt is provided about an outwardlyfacing surface of a piston movable within a housing of a valve forsterile transfer of fluids with the rib being formed around the externalsurface of the skirt.
 12. A seal as claimed in claim 7, in which theskirt is provided as an attachment connectable to the member via acoupling means.
 13. A seal as claimed in claim 7, in which the couplingmeans comprises a snap-fit arrangement between the skirt and the othermember.
 14. A seal as claimed in claim 7, in which the snap-fitarrangement comprises a series of alternating resiliently deformableribs and grooves formed around each of the mutually facing surfaces ofthe skirt and the other member the ribs of the skirt and the othermember being deformable on assembly so as to engage with thecorresponding grooves of the member and the skirt.
 15. A seal as claimedin claim 7, in which the skirt is formed integrally with the member byforming an endless slot in the material of the member so that the slotis defined by mutually facing endless surfaces of the skirt and themember.
 16. A seal as claimed in claim 7, in which the skirt ismanufactured from plastics material.
 17. A seal as claimed in claim 7,in which the skirt is configured to be sufficiently resilientlydeformable under a predetermined pressure range of fluid supplied into agap between the mutually facing surfaces of the skirt and the member towhich the skirt is attached, so as to deflect towards the other memberthus enhancing the sealing action of the at least one rib between theskirt and the other member.